Type:
Module
The Comparable mixin is used by classes whose objects may be
ordered. The class must define the <=> operator, which
compares the receiver against another object, returning -1, 0, or +1
depending on whether the receiver is less than, equal to, or greater than
the other object. If the other object is not comparable then the
<=> operator should return nil. Comparable
uses <=> to implement the conventional comparison
operators (<, <=, ==,
>=, and >) and the method
between?.
class SizeMatters
include Comparable
attr :str
def <=>(anOther)
str.size <=> anOther.str.size
end
def initialize(str)
@str = str
end
def inspect
@str
end
end
s1 = SizeMatters.new("Z")
s2 = SizeMatters.new("YY")
s3 = SizeMatters.new("XXX")
s4 = SizeMatters.new("WWWW")
s5 = SizeMatters.new("VVVVV")
s1 < s2 #=> true
s4.between?(s1, s3) #=> false
s4.between?(s3, s5) #=> true
[ s3, s2, s5, s4, s1 ].sort #=> [Z, YY, XXX, WWWW, VVVVV]